Refactor LoopHandler to avoid calling KernelAstAdapter.getNode

pkg/compiler/lib/src/ssa/builder.dart

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 import 'dart:collection';
 
 import 'package:js_runtime/shared/embedded_names.dart';
 
 import '../closure.dart';
 import '../common.dart';
@@ skipping 1726 matching lines @@
     }
 
     loopHandler.handleLoop(node, () {}, buildCondition, () {}, () {
       visit(node.body);
     });
   }
 
   visitDoWhile(ast.DoWhile node) {
     assert(isReachable);
     LocalsHandler savedLocals = new LocalsHandler.from(localsHandler);
-    localsHandler.startLoop(node);
+    ClosureScope scopeData = localsHandler.closureData.capturingScopes[node];
+    localsHandler.startLoop(scopeData);

[Emily Fortuna, 2017/06/09 20:12:26]

great minds think alike?

I actually have a CL that does this same thing (passing in the data instead of
the node) that I was working on yesterday evening, but didn't send out yet for
review: https://codereview.chromium.org/2932103002 

So... maybe hold off on this part? I didn't do the change about making the
localsMap non-private though, so that could go in. I should have this other CL
ready for review by EOD today, so you can take a look -- it's in a similar but
slightly different direction than this one, so I welcome your input.

[Johnni Winther, 2017/06/12 08:02:52]

I'll wait for your CL to land

     loopDepth++;
     JumpHandler jumpHandler = loopHandler.beginLoopHeader(node);
     HLoopInformation loopInfo = current.loopInformation;
     HBasicBlock loopEntryBlock = current;
     HBasicBlock bodyEntryBlock = current;
     JumpTarget target = elements.getTargetDefinition(node);
     bool hasContinues = target != null && target.isContinueTarget;
     if (hasContinues) {
       // Add extra block to hang labels on.
       // It doesn't currently work if they are on the same block as the
       // HLoopInfo. The handling of HLabeledBlockInformation will visit a
       // SubGraph that starts at the same block again, so the HLoopInfo is
       // either handled twice, or it's handled after the labeled block info,
       // both of which generate the wrong code.
       // Using a separate block is just a simple workaround.
       bodyEntryBlock = openNewBlock();
     }
-    localsHandler.enterLoopBody(node);
+    localsHandler.enterLoopBody(scopeData);
     visit(node.body);
 
     // If there are no continues we could avoid the creation of the condition
     // block. This could also lead to a block having multiple entries and exits.
     HBasicBlock bodyExitBlock;
     bool isAbortingBody = false;
     if (current != null) {
       bodyExitBlock = close(new HGoto());
     } else {
       isAbortingBody = true;
@@ skipping 5060 matching lines @@
       this.oldReturnLocal,
       this.oldReturnType,
       this.oldResolvedAst,
       this.oldStack,
       this.oldLocalsHandler,
       this.inTryStatement,
       this.allFunctionsCalledOnce,
       this.oldElementInferenceResults)
       : super(function);
 }